基于 Redis + Lua 脚本实现分布式锁，确保操作的原子性

1.加锁的Lua脚本： lock.lua

--- -1 failed
--- 1 success--- getLock key
local result = redis.call('setnx' , KEYS[1] , ARGV[1])
if result == 1 then--PEXPIRE:以毫秒的形式指定过期时间redis.call('pexpire' , KEYS[1] , 3600000)
elseresult = -1;-- 如果value相同，则认为是同一个线程的请求，则认为重入锁local value = redis.call('get' , KEYS[1])if (value == ARGV[1]) thenresult = 1;redis.call('pexpire' , KEYS[1] , 3600000)end
end
--  如果获取锁成功，则返回 1
return result

2.解锁的Lua脚本： unLock.lua

if redis.call('get', KEYS[1]) == ARGV[1]thenreturn redis.call('del', KEYS[1])elsereturn 0
end

3.将资源文件放在资源文件夹下

4.Java中调用lua脚本

1）获取文件方式

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.scripting.support.ResourceScriptSource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.Arrays;/*** @Author: best_liu* @Description:* @Date Create in 14:04 2023/10/26* @Modified By:*/
@Slf4j
@RestController
public class LuaLock {@Autowiredprivate RedisTemplate redisTemplate;@GetMapping(value = "/getLock")public Long getLock() {DefaultRedisScript<Long> script = new DefaultRedisScript<Long>();script.setResultType(Long.class);
//        获取lua文件方式script.setScriptSource(new ResourceScriptSource(new ClassPathResource("script/lock.lua")));Long execute = (Long) redisTemplate.execute(script, Arrays.asList("best_liu"),"best_liu20231026150600");return execute;}
}

2）lua字符串方式

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.Arrays;/*** @Author: best_liu* @Description:* @Date Create in 14:04 2023/10/26* @Modified By:*/
@Slf4j
@RestController
public class LuaLock {@Autowiredprivate RedisTemplate redisTemplate;@GetMapping(value = "/getLock")public Long getLock() {DefaultRedisScript<Long> script = new DefaultRedisScript<Long>();script.setResultType(Long.class);
//        获取lua文件方式
//        script.setScriptSource(new ResourceScriptSource(new ClassPathResource("script/lock.lua")));String lua = "local result = redis.call('setnx' , KEYS[1] , ARGV[1])\n" +"if result == 1 then\n" +"    redis.call('pexpire' , KEYS[1] , 3600000)\n" +"else\n" +"    result = -1;\n" +"    local value = redis.call('get' , KEYS[1])\n" +"    if (value == ARGV[1]) then\n" +"        result = 1;\n" +"        redis.call('pexpire' , KEYS[1] , 3600000)\n" +"    end\n" +"end\n" +"return result";script.setScriptText(lua);Long execute = (Long) redisTemplate.execute(script, Arrays.asList("best_liu"),"best_liu20231026150600");return execute;}
}

5.jedis调用Lua脚本实现分布式重试锁

1）引入jedis依赖

<!-- jedis --><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>2.9.0</version></dependency>

2）jedis调用lua

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import redis.clients.jedis.Jedis;import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;@Slf4j
@RestController
public class LuaLock {@GetMapping(value = "/getLock")public Long getLock() {//获取连接Jedis jedis = new Jedis("127.0.0.1", 6379);String lua = "local result = redis.call('setnx' , KEYS[1] , ARGV[1])\n" +"if result == 1 then\n" +"    redis.call('pexpire' , KEYS[1] , ARGV[2])\n" +"else\n" +"    result = -1;\n" +"    local value = redis.call('get' , KEYS[1])\n" +"    if (value == ARGV[1]) then\n" +"        result = 1;\n" +"        redis.call('pexpire' , KEYS[1] , ARGV[2])\n" +"    end\n" +"end\n" +"return result";List<String> keys = new ArrayList<>();List<String> values = new ArrayList<>();keys.add("best_liu");values.add("best_liu20231026150600");values.add("3600000");Object result = jedis.eval(lua, keys, values);System.out.println(result);return 1L;}
}